If you no longer need to support 10.4, you can use the LSSharedFileList API that Apple introduced in 10.5 to manage Login Items. Information on that API does not yet appear in the official documentation, but you can find example code here and here.

As far as I know, Apple still does not provide a way to easily manage Dock items. I believe this is by design. The Dock is supposed to controlled by the user. However, I’ve found that users sometimes want an application to add or remove itself from the Dock for convenience.

Login Items

This code uses NSUserDefaults to modify the settings files for the user’s Login Items. If the System Preferences application is open, it must be closed and reopened to see the changes.

Dock

The code for adding applications to and removing them from the user’s Dock is very similar. The differences include the domain, key, predicate and dictionary entry.

This code uses NSUserDefaults to modify the settings files for the user’s Dock. The Dock must also be restarted after making a change. The command “killall Dock” works, either programmatically or from the Terminal.

For security reasons, Apple recommends that GUI applications should never run with the privileges of the root user. GUI applications normally load several types of plugins and input managers automatically. If a malicious plugin was installed then it could cause security problems when the privileged application was launched.

In addition, system services that run with the privileges of the root user (such as launch daemons) need to avoid using certain technology frameworks provided by Apple. These frameworks are not safe to use in a service that runs with the privileges of the root user.

If you need your GUI application to do something that requires root privileges, Apple recommends you split your application into two parts. First, create a GUI that runs as a normal user. Then when you need to do something with root privileges, you launch a separate helper process or tool. Splitting your application avoids security holes while keeping things very easy for your users.

Two Steps

Launching a privileged process is done in two steps:

1) Request authorization. The operating system will ask the user for permission to run a privileged process. The user will need to enter an administrator’s username and password.

Please note that the authorization reference created in the first function is released in the second function. If you want to launch several privileged processes in a short amount of time, you can comment out this line and and release the reference on your own afterwards.

Some of Apple’s sample code (and other examples) has an extra step where they copy the authorization reference. This is only necessary if you have a previously created authorization reference that you want to add elevated privileges to.

Just One Step

If you don’t need to update your GUI between these two steps, then both actions can be combined into one step.

Mac OS X has an easy way to type “curly” quotes and apostrophes instead of "straight" versions. I used both versions in that sentence to show the difference. Here is a bigger version to make the distinction more visible:

Many people think “curly” quotes look better than "straight" ones.

You can use the following keyboard shortcuts to type a single or double curly quote:

Single quote open (‘) — option ]

Single quote close (’) — shift option ]

Double quote open (“) — option [

Double quote close (”) — shift option [

However, I think it makes more sense to use [ and ] for open and close versions instead of the shift key. I found myself constant typing “mismatched‘ quotes. I also wanted to use the shift key for double quotes since that’s how the normal keyboard button works.

Single quote open (‘) — option [

Single quote close (’) — option ]

Double quote open (“) — option shift [

Double quote close (”) — option shift ]

Since OS X supports custom key bindings, I looked for a way to fix this. The trick is to create a file called DefaultKeyBinding.dict in the KeyBindings folder inside your Library folder. You can use this file to override the default key bindings for most applications.

Here are my changes. Please feel free to copy the settings below and save them to your own computer. You may need to create the KeyBindings folder if it isn’t already there.

There is sample code on the Internet for programmatically checking the system idle time using IOKit and Cocoa (see here, for example). However, most of the examples seem overly long (see Paul Graham’s Succinctness is Power). The code below works in Tiger/10.4 and later and is about as concise as I can make it while still handling errors properly.

Mac OS X is well known for its great support for PDF files. You can create a PDF file from anything you can print. I thought that using Apple’s PDFKit framework would make it easy to program a way to print an existing PDF file. That turned out not to be the case.

Sending a file to a printer using the lp command is easy. However, this approach does not work for PDF files formatted for landscape printing. You can specify landscape orientation, but I wanted a way to detect the orientation automatically.

PDFKit has a PDFView object that has a printWithInfo:autoRotate: method. However, adding a PDFDocument to a PDFView and telling it to print doesn’t work. I eventually stumbled onto the fact that PDFDocumenthas a secret method that makes printing easy. So here is the code:

First, a disclaimer. Apple will warn you not to do this. The only supported way of creating an alias is to use the Finder. If you must do it programmatically, you will be told to use AppleScript. But if AppleScript won’t work for you, and a simple Cocoa method is what you want, read on.

Mozy’s Mac client doesn’t create aliases, but our customers do. We want to make sure our software backs them up correctly. So we added some unit tests to our build process that create aliases and check to see that Mozy handles them correctly.

We first used AppleScript, but ran quickly into two issues:

Our build server runs as the root user, which doesn’t have a UI context. AppleScript doesn’t work without a UI context.

Even running as a normal user, AppleScript cannot access the system temporary files location (/tmp) which is where we wanted to create our aliases.

That’s when the fun began.

I spent quite a bit of time failing to find the right bit of magic to create an alias that functioned properly in Finder. It turns out that an alias is a data structure inside another data structure stored in the resource fork of an empty file. Those structures need to have the correct record types for everything to work.

Having gone to the trouble of figuring this out, I thought I’d share. This code creates an alias for a folder, but it should serve as a good template if you need to create another type.

I consider this code to be in the public domain. Please feel free to copy and paste. And let me know if you find any problems or have suggestions.

If you need a complete solution, Nathan Day wrote a nice set of classes called NDAlias. We didn’t want to import 9 classes for just a handful of unit tests.

I later found some of Apple’s sample code from 1999 demonstrating a similar approach. I think our Objective-C example is much easier to use.

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Interactive Fiction Novel App

Discontinued 11 Feb 2005

Apps are perfect for interactive fiction. I was lucky enough to work on a beautiful app with a wonderful story for 2.5 years. My company, Story Ideals Interactive, no longer has permission to publish the story or to finish it.